Measurement Invariance of the Readiness to Change Questionnaire Among Injured Patients Who Received a Brief Intervention for Alcohol Use.

We tested measurement invariance of the Readiness to Change Questionnaire (RCQ) to evaluate its utility in assessing the stages of change in the context of brief intervention for alcohol use in opportunistic settings. Participants ( = 596) were patients admitted from three Level I trauma centers who were randomly assigned to one of three brief alcohol interventions. The RCQ was administered at baseline and 3-month follow-up. The RCQ was scalar invariant across biological sex and partially scalar invariant across race/ethnicity and alcohol use severity. Hispanic participants were higher on contemplation and action and Black participants were higher on action than White participants. Hazardous drinkers were lower in precontemplation and higher in contemplation and action than nonhazardous drinkers. The RCQ was scalar invariant across intervention conditions and time. Brief motivational intervention with a booster increased action from baseline to 3 month. These findings provide further support for the use of the RCQ.